Structural electronics wireless sensor nodes

ABSTRACT

A structural electronics wireless sensor node is provided that includes layers of electronic components fabricated from patterned nanostructures embedded in an electrically conductive matrix. In some aspects, the structural electronics wireless sensor node includes a plurality of nanostructure layers that each form individual electronic components of the structural electronics wireless sensor node. In certain embodiments, the structural electronics wireless sensor node includes electronic components such as a resistor, a inductor, a capacitor, and/or an antenna.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims the benefit as a Continuation-in-part ofInternational Patent Application Serial No. PCT/US2018/065422, filedDec. 13, 2018 under Attorney Docket No. G0766.70219WO00, and entitled“STRUCTURAL ELECTRONICS WIRELESS SENSOR NODES,” which is herebyincorporated herein by reference in its entirety.

Application PCT/US2018/065422 claims the benefit under 35 U.S.C. §119(e) of U.S. Provisional Application No. 62/598,416, filed Dec. 13,2017 under Attorney Docket No. G0766.70235US00, and entitled “Resistor,Inductor, and Capacitor Structural Electronics Elements,” which ishereby incorporated herein by reference in its entirety.

Application PCT/US2018/065422 claims the benefit under 35 U.S.C. §119(e) of U.S. Provisional Application No. 62/598,425, filed Dec. 13,2017 under Attorney Docket No. G0766.70236US00, and entitled “FlexiblePatch Antenna,” which is hereby incorporated herein by reference in itsentirety.

Application PCT/US2018/065422 claims the benefit under 35 U.S.C. §119(e) of U.S. Provisional Application No. 62/598,428, filed Dec. 13,2017 under Attorney Docket No. G0766.70234US00, and entitled “StructuralElectronics Passive Wireless Sensor Nodes,” which is hereby incorporatedherein by reference in its entirety.

Application PCT/US2018/065422 claims the benefit under 35 U.S.C. §119(e) of U.S. Provisional Application No. 62/598,430, filed Dec. 13,2017 under Attorney Docket No. G0766.70219US00, and entitled “AdvancedManufacturing Structural Electronics,” which is hereby incorporatedherein by reference in its entirety.

FIELD OF THE DISCLOSURE

The present disclosure relates generally to wireless sensor nodes thatinclude components fabricated from patterned nanostructures.

BACKGROUND

Sensor systems are sometimes used for sensing various environmental andother state conditions. Conventional sensor systems may include atransceiver that can be used to communicate with an external device. Insuch cases, the sensor systems use an external or internal energy source(e.g., a battery-powered energy source) to operate the transceiverand/or other components of the sensor system. Inclusion of thetransceiver and/or internal energy source oftentimes results in bulkysensor systems that consumes high power, usually in the range of 1-10milliwatts. Such systems cannot be readily deployed at certain sitesand/or locations where smaller packaging is desirable.

SUMMARY OF THE DISCLOSURE

Structural electronics wireless sensor nodes that include componentsfabricated from patterned nanostructures are generally described.

In some embodiments, a structural electronics wireless sensor node isdescribed, wherein the structural electronics wireless sensor nodecomprises a first nanostructure layer comprising a first plurality ofpatterned nanostructures embedded in an electrically insulating matrix,wherein the first nanostructure layer serves a first electronic functionof the wireless sensor node. In some embodiments, the structuralelectronics wireless sensor node comprises at least a secondnanostructure layer of the body comprising a second plurality ofpatterned nanostructures embedded in an electrically insulating matrix,wherein the second nanostructure layer serves a second electronicfunction of the wireless sensor node. In certain embodiments, the firstnanostructure layer is electrically coupled to the second nanostructurelayer.

According to some embodiments, a structural electronics wireless sensornode comprises a plurality of nanostructure layers, each layercomprising respective pluralities of patterned nanostructures embeddedin an electrically insulating matrix, wherein each layer serves adifferent electronic function of the wireless sensor node and the layersare electrically coupled by an electrical connection.

According to certain embodiments, a method of fabricating a structuralelectronics wireless sensor node is described, wherein the structuralelectronics wireless sensor node comprises a plurality of nanostructurelayers. In some embodiments, the method comprises sputtering a solutionof nanostructures on a substrate, providing an electrically insulatingmaterial, embedding the forest of parallel patterned nanostructures inthe electrically insulating material, thereby providing a firstnanostructure layer comprising parallel patterned nanostructuresembedded in an electrically insulating matrix, electrically coupling thefirst nanostructure layer to at least a second nanostructure layercomprising parallel patterned nanostructures embedded in an electricallyinsulating matrix, and integrating the structural wireless sensor nodeinto a manufactured product.

In some embodiments, a structural electronics wireless sensor node isdescribed, wherein the structural electronics wireless sensor nodecomprises a first nanostructure layer comprising a first plurality ofpatterned nanostructures embedded in an electrically insulating matrix,wherein the first nanostructure layer is a resistor of the wirelesssensor node, a second nanostructure layer comprising a second pluralityof patterned nanostructures embedded in an electrically insulatingmatrix, wherein the second nanostructure layer is an inductor of thewireless sensor node, and a third nanostructure layer comprising a thirdplurality of patterned nanostructures embedded in an electricallyinsulating matrix, wherein the third nanostructure layer is a capacitorof the wireless sensor node. In certain embodiments, the firstnanostructure layer, second nanostructure layer, and third nanostructurelayer are electrically coupled.

According to certain embodiments, a structural electronics wirelesssensor node comprises a plurality of nanostructure layers, each layercomprising respective pluralities of patterned nanostructures embeddedin an electrically insulating matrix, wherein a first nanostructurelayer is a resistor of the wireless sensor node, a second nanostructurelayer is an inductor of the wireless sensor node, and a thirdnanostructure layer is a capacitor of the wireless sensor node. In someembodiments, the structural wireless sensor node comprises an electricalconnection between the plurality of nanostructure layers.

In some embodiments, a structural electronics element is described,wherein the structural electronics element comprises a first carbonnanotube layer comprising a plurality of patterned carbon nanotubesembedded in a structural polymer matrix, wherein the first carbonnanotube layer is a resistor of a wireless sensor node, and wherein thefirst carbon nanotube layer is configured in a planar fashion with atleast a second carbon nanotube layer and/or is stacked vertically withat least a second carbon nanotube layer.

In some embodiments, a structural electronics element comprises a firstcarbon nanotube layer comprising a plurality of patterned carbonnanotubes embedded in a structural polymer matrix, wherein the firstcarbon nanotube layer is an RF resistor of a RF impedance matchingcircuit, and wherein the first carbon nanotube layer is configured in aplanar fashion with at least a second carbon nanotube layer and/or isstacked vertically with at least a second carbon nanotube layer.

In certain embodiments, a structural electronics element comprises afirst carbon nanotube layer comprising a plurality of patterned carbonnanotubes embedded in a structural polymer matrix, wherein the firstcarbon nanotube layer is an inductor of a wireless sensor node, andwherein the first carbon nanotube layer is configured in a planarfashion with at least a second carbon nanotube layer and/or is stackedvertically with at least a second carbon nanotube layer.

According to some embodiments, a structural electronics elementcomprises a first carbon nanotube layer comprising a plurality ofpatterned carbon nanotubes embedded in a structural polymer matrix,wherein the first carbon nanotube layer is a resistor of a wirelesssensor node, and wherein the first carbon nanotube layer is configuredin a planar fashion with at least a second carbon nanotube layer and/oris stacked vertically with at least a second carbon nanotube layer.

In certain embodiments, an antenna is described, wherein the antennacomprises a nanostructure layer comprising a plurality of patternednanostructures embedded in an electrically insulating matrix, whereinthe antenna serves an electronic function of a wireless sensor node.

Other advantages and novel features of the present technology willbecome apparent from the following detailed description of variousnon-limiting embodiments of the technology when considered inconjunction with the accompanying figures. In cases where the presentspecification and a document incorporated by reference includeconflicting and/or inconsistent disclosure, the present specificationshall control.

BRIEF DESCRIPTION OF DRAWINGS

Various aspects and embodiments of the application will be describedwith reference to the following figures. It should be appreciated thatthe figures are not necessarily drawn to scale. Items appearing inmultiple figures are indicated by the same reference number in all thefigures in which they appear.

FIG. 1A illustrates a forest of vertically aligned patternednanostructures grown on a substrate, in accordance with certainembodiments;

FIG. 1B illustrates a forest of parallel patterned nanostructures on asubstrate, in accordance with some embodiments;

FIG. 1C illustrates the introduction of an electrically insulatingmaterial to a forest of parallel patterned nanostructures on asubstrate, in accordance with certain embodiments;

FIG. 1D illustrates a nanostructure layer of a structural electronicswireless sensor node comprising parallel patterned nanostructuresembedded in an electrically insulating matrix, in accordance with someembodiments;

FIG. 2A illustrates the introduction of a second substrate to a firstnanostructure layer comprising parallel patterned nanostructuresembedded in an electrically insulating matrix, in accordance withcertain embodiments;

FIG. 2B illustrates a first nanostructure layer comprising parallelpatterned nanostructures embedded in an electrically insulating matrixand a second nanostructure layer comprising parallel patternednanostructures embedded in an electrically insulating matrix, inaccordance with some embodiments;

FIG. 3A illustrates a first nanostructure layer and a secondnanostructure layer configured in a planar fashion forming a structuralelectronics wireless sensor node, according with certain embodiments;

FIG. 3B illustrates a first nanostructure layer and a secondnanostructure layer stacked vertically forming a structural electronicswireless sensor node, in accordance with some embodiments;

FIG. 4 is a flow chart of a non-limiting method of fabricating awireless sensor node, in accordance with certain embodiments;

FIG. 5A illustrates a structural wireless sensor node comprising a firstnanostructure layer, a second nanostructure layer, and a thirdnanostructure layer configured in a planar fashion forming a structuralelectronics wireless sensor node, in accordance with some embodiments;

FIG. 5B illustrates a structural wireless sensor node comprising a firstnanostructure layer, a second nanostructure layer, a third nanostructurelayer, and a fourth nanostructure layer configured in a planar fashionforming a structural electronics wireless sensor node, in accordancewith some embodiments;

FIG. 5C illustrates a structural wireless sensor node comprising a firstnanostructure layer, a second nanostructure layer, and a thirdnanostructure layer stacked vertically forming a structural electronicswireless sensor node, in accordance with certain embodiments;

FIG. 5D illustrates a structural wireless sensor node comprising a firstnanostructure layer, a second nanostructure layer, a third nanostructurelayer, and a fourth nanostructure layer stacked vertically forming astructural electronics wireless sensor node, in accordance with certainembodiments;

FIG. 5E illustrates a structural wireless sensor node comprising a firstnanostructure layer, a second nanostructure layer, a third nanostructurelayer, and a fourth nanostructure layer, wherein at least a portion ofthe nanostructure layers are configured in a planar fashion and at leasta portion of the nanostructure layers are stacked vertically, inaccordance with certain embodiments;

FIG. 6 illustrates a non-limiting method of fabricating a resistor,according to certain embodiments;

FIG. 7 illustrates a non-limiting method of fabricating an inductor,according to some embodiments;

FIG. 8 illustrates a series of fabricated inductors, according tocertain embodiments;

FIG. 9 illustrates a non-limiting method of fabricating a capacitor,according to some embodiments;

FIG. 10A illustrates a resistor, inductor, and capacitor structuralelectronic components of a wireless sensor node, according to certainembodiments;

FIB. 10B shows a non-limiting embodiment of a structural electronicswireless sensor node comprising an inductor and a capacitor.

FIG. 11 illustrates an impedance matching element of a wireless sensornode, according to certain embodiments;

FIG. 12 is a flow chart of a non-limiting method of fabricating aflexible patch antenna;

FIG. 13A illustrates a perspective view of a flexible patch antenna,according to certain embodiments;

FIG. 13B shows a fabricated flexible patch antenna, according to certainembodiments;

FIG. 14 illustrates an exemplary embodiment of a wireless structuralelectronic sensor node, according to some embodiments;

FIG. 15 illustrates the integration of a structural wireless sensor nodeinto a manufactured product, according to certain embodiments;

FIG. 16 shows a plot of the insertion loss S 11 as a function offrequency for a fabricated antenna, according to certain embodiments,according to some embodiments;

FIG. 17A shows a plot of the resistivity of a structural electronicsresistor with CNTs as a function of CNT length, according to certainembodiments;

FIG. 17B shows a plot of the sheet resistance of a structuralelectronics resistor with CNTs as a function of CNT length, according tosome embodiments;

FIG. 17C shows a plot of the impedance of a structural electronicsresistor as a function of frequency, according to certain embodiments;

FIG. 17D shows an alternate plot of the impedance of a structuralelectronics resistor as a function of frequency, according to someembodiments;

FIG. 18A shows the set-up for testing the piezoresistivity of astructural electronics resistor, according to certain embodiments;

FIG. 18B shows the piezoresistivity results, with stress of thestructural electronics resistor shown as a function of microstrain, asis dR/R;

FIG. 18C shows a plot of the gauge factor of a structural electronicsresistor as a function of microstrain, according to certain embodiments;

FIG. 19A shows a plot of the impedance of a structural electronicscapacitor as a function of frequency, according to some embodiments;

FIG. 19B shows the reactance of the structural electronics capacitor asa function of frequency, according to certain embodiments;

FIG. 20A shows a plot of the impedance of a structural electronicsinductor as a function of frequency, according to some embodiments;

FIG. 20B shows the reactance of the structural electronics inductors forwhich the impedance is shown in FIG. 20A;

FIG. 21A shows the dynamic mechanical analysis of a polymernanocomposite with CNTs of length 50 microns, 150 microns, and 500microns;

FIG. 21B shows the same type of data as FIG. 21A, but for the situationin which the tensile stress is perpendicular to the CNT axis;

FIG. 21C shows the dynamic mechanical analysis of a polymernanocomposite with CNTs as a function of CNT length, according to someembodiments;

FIG. 22A shows a plot of the capacitance of a structural electronicscapacitor as a function of frequency; and

FIG. 22B shows a plot of the inductance of a structural electronicsinductor as a function of frequency.

DETAILED DESCRIPTION

The embodiments described herein set forth structural electronicswireless sensor nodes that include components fabricated fromsemi-conducting or conducting patterned nanostructures (e.g., carbonnanostructures) in an electrically insulating matrix. As used herein,structural electronics can refer to a structure that has electroniccomponents as an integral part of the material, and as a result, theelectronics are not separable from the structural components. Formingthe components of the structural electronics wireless sensor nodes frompatterned nanostructures facilitates the ability to achieve small systemor device size, for instance on the microscale or nanoscale. Forexample, in some embodiments, the structural electronics wireless sensornode is a compact stand-alone sensor contained within a housing and/orbody that lacks external electrical connections, contacts, and/orconnections (e.g., pins). In some embodiments, the structuralelectronics wireless sensor node may therefore represent an example of azero-pin sensor. Furthermore, in certain embodiments wherein thecomponents include patterned nanostructure embedded in an electricallyinsulating material, the strength (e.g., tensile strength), stiffness,and/or toughness of the nanostructures is at least the same as thestrength, stiffness, and/or toughness of the electrically insulatingmaterial. Resultantly, the structural electronics wireless sensor nodeis configured to function as both a structure and an electronicselement.

In some embodiments, the structural electronics wireless sensor node isconfigured to communicate sensed data wirelessly (e.g., viabackscattering). Accordingly, in certain embodiments, the structuralelectronics wireless sensor node can advantageously be constructedwithout a transceiver. In some aspects, the structural electronicswireless sensor node is configured to generate energy to implementbackscattering and provide power to various components of the sensorsystem. Resultantly, in certain embodiments, the structural electronicswireless sensor node may be constructed without an internal energysource, such as a battery-powered energy source. By constructing thestructural electronics wireless sensor node without a transceiver and/orinternal energy source, the wireless sensor node can operate atsubstantially lower power than wireless sensor nodes that include atransceiver and/or internal energy source. For example, in someembodiments, the structural electronics wireless sensor node consumesless than 100 microwatts in operation, less than 50 microwatts inoperation, less than 40 microwatts in operation, less than 30 microwattsin operation, or any value or range of values within that range.Alternatively, in some embodiments, the structural electronics wirelesssensor node may be constructed with an internal energy source (e.g., abattery-powered energy source).

The embodiments described herein set forth structural electronicswireless sensor nodes that include resistor, inductor, and capacitor(RLC) components fabricated from patterned nanostructures. In someaspects, the structural electronics wireless sensor node may include anantenna (e.g., a flexible patch antenna, although it need not beflexible in all embodiments) fabricated from patterned nanostructures.In certain embodiments, the structural electronics wireless sensor nodemay comprise a transistor (e.g., a field-effect transistor). Forming theRLC components, antenna, and/or transistor of the structural electronicswireless sensor node from patterned nanostructures facilitates theability to achieve a microscale and/or nanoscale system and/or devicesize.

Improved wireless sensor systems and methods of making the same aredesirable. Aspects of the present application provide such systems andmethods.

The aspects and embodiments described above, as well as additionalaspects and embodiments, are further described below. These aspectsand/or embodiments may be used individually, all together, or in anycombination of two or more, as the application is not limited in thisrespect.

Some embodiments described herein relate to a structural electronicswireless sensor node. In some embodiments, the body of the structuralelectronics wireless sensor node comprises at least a firstnanostructure layer and a second nanostructure layer, as is described infurther detail below. In certain embodiments, the nanostructures of thefirst nanostructure layer and/or second nanostructure layer aresemi-conducting or conducting.

The term “nanostructure” is used herein in a manner consistent with itsordinary meaning in the art and refers to a structure that has acharacteristic dimension, such as a cross-sectional diameter, or otherappropriate dimension, that is greater than or equal to 1 nm and lessthan 1 micrometer. Specific characteristic dimensions of thenanostructure are described in more detail below. In some embodiments,the nanostructure is any of a variety of suitable nanostructures, suchas a nanofiber, a nanowire, a nanorod, a nanoparticle, and/or the like.In certain aspects, the nanostructures are electrically conductive. Thenanostructure may be an elongated nanostructure with a high aspect ratio(e.g., greater than 10, 100, 1,000, 10,000, or greater).

In certain embodiments, the nanostructures comprise carbon-basednanostructures. For example, in certain embodiments, the nanostructurescomprise carbon nanotubes (CNTs). The term “carbon nanotube” is usedherein in a manner consistent with its ordinary meaning in the art andrefers to a substantially cylindrical molecule or nanostructurecomprising a fused network of primarily six-membered rings (e.g.,six-membered aromatic rings) comprising primarily carbon atoms. Furtherdetails regarding CNTs are described below.

In some embodiments, the nanostructures comprise metal. In someembodiments the metal is a semi-conducting or conducting metal. Forexample, the nanostructure may comprise silicon (Si), germanium (Ge),gold (Au), metal oxides (e.g., In₂O₃, SnO₂, ZnO), and/or the like.

In some embodiments, the body of the structural electronics wirelesssensor node comprises a plurality of nanostructure layers (e.g., CNTlayers). For example, in some embodiments, the body of the structuralelectronics wireless sensor node comprises two or more (e.g., three,four, five, six, etc.) nanostructure layers. In some aspects, the bodyof the structural electronics wireless sensor node is three-dimensional.In certain embodiments, the nanostructure layers are configured in aplanar fashion. For example, a first nanostructure layer and a secondnanostructure layer are configured in a planar fashion if the edges ofthe first nanostructure layer and the edges of the second nanostructurelayer intersect only at their endpoints. In some embodiments, thenanostructure layers are stacked vertically. For example, a firstnanostructure layer and a second nanostructure layer are stackedvertically if at least a portion of a surface of the first nanostructurelayer overlaps with at least a portion of a surface of the secondnanostructure layer. In certain embodiments wherein the body of thestructural electronics wireless sensor node comprises at least threenanostructure layers, at least a portion of the nanostructure layers mayconfigured in a planar fashion and at least a portion of thenanostructure layers may be stacked vertically.

According to some embodiments, each of the nanostructure layers comprisea plurality of patterned nanostructures embedded in an electricallyinsulating matrix. In certain embodiments, the electrically insulatingmatrix is a structural polymer matrix and/or a ceramic matrix. Accordingto certain embodiments, the structural polymer matrix comprises any of avariety of suitable polymer materials. For example, in certainembodiments, the structural polymer matrix is a substrate suitable forembedding nanostructures (e.g., CNTs). In some embodiments, thestructural polymer matrix is a dielectric polymer, a thermoplastic, apolymer film, a fiber-reinforced polymer composite layer (e.g., aprepreg layer), or any other polymer form that is amenable tolayer-by-layer construction. As used herein, the term “prepreg” refersto one or more layers of thermoset or thermoplastic resin containingembedded fibers, for example fibers of carbon, glass, silicon carbide,and the like. In some embodiments, the structural polymer matrix is anepoxy resin (e.g., EPON resin), paramethylstyrene (PMS),para-methoxyamphetamine (PMA), a polyimide, polyether ether ketone(PEEK), polyether ketone ketone (PEKK), bis-maleimide (BMI), a cyanateester, or combinations thereof.

The nanostructure layers of structural electronics body may befabricated by any of a variety of suitable techniques, which isdescribed herein with reference to the figures. For example, FIG. 1Aillustrates a forest of vertically aligned patterned nanostructuresgrown on a substrate, according to some embodiments. As shown in FIG.1A, a forest of vertically aligned patterned nanostructures 104 is grownon substrate 102 a. As used herein, a “forest” of nanostructures (e.g.,elongated nanostructures) corresponds to a plurality of nanostructuresarranged in side-by-side fashion with one another. In some embodiments,the nanostructures are patterned by any of a variety of suitable growthmethods. For example, according to certain embodiments, the method ofgrowing nanostructures includes providing an active growth material oran active growth material precursor and exposing a precursor of thenanostructures to the active growth material or active growth materialprecursor. In some aspects, the active growth material or active growthmaterial precursor may be a mask on the substrate. According to certainembodiments, the active growth material or active growth materialprecursor may be provided on the substrate in any of a variety ofdesired patterns, and the nanostructures may be grown in any of avariety of desired patterns, within such predetermined variance. In someembodiments, the method comprises sputtering a solution ofnanostructures on the substrate. Additional growth methods are describedherein in greater detail. The substrate used to grow the nanostructuresmay be any of a variety of suitable substrates, such as a glass fiber, acarbon fiber, a silicon substrate, and the like. According to certainembodiments, the forest of vertically patterned nanostructures may be ofany desirable length, width, and/or thickness.

In some embodiments, the forest of vertically aligned patternednanostructures may be knocked down to provide a forest of parallelpatterned nanostructures on a substrate. FIG. 1B illustrates a forest ofparallel patterned nanostructures on a substrate, according to certainembodiments. As shown in FIG. 1B, roller 106 may be used to knock downforest of vertically aligned patterned nanostructures 104 (shown in FIG.1A), thereby providing forest of parallel patterned nanostructures 108on substrate 102 a. Without wishing to be bound by theory, thevertically aligned patterned nanostructures may be knocked down by anyof a variety of suitable techniques including mechanically (e.g., with aroller, with a glass rod, or with another suitable mechanicalinstrument), with a solvent, or by any other suitable manner.

Alternatively, in certain non-limiting embodiments, a nanostructure matmay be provided and patterned in order to provide a forest of verticallyaligned patterned nanostructures on a substrate. For example, in somenon-limiting embodiments buckypaper may be provided and patterned.

In certain embodiments, an electrically insulating material is providedto the forest of parallel patterned nanostructures in order to embed theparallel patterned nanostructures in an electrically insulating matrix(e.g., a structural polymer matrix). The electrically insulatingmaterial may be provided by any of a variety of suitable techniques,such as drop-casting. FIG. 1C illustrates the introduction of anelectrically insulating material to a forest of parallel patternednanostructures on a substrate, according to some embodiments. As shownin FIG. 1C, electrically insulating material 110 is drop-casted ontoforest of parallel patterned nanostructures 108 on substrate 102 a. Incertain embodiments, the parallel patterned nanostructures and theelectrically insulating material may be spin-coated, thermally cured,thermally processed, deposited, and/or delaminated in order to embed theparallel patterned nanostructure in the electrically insulatingmaterial.

In certain embodiments, the nanostructures and the electricallyinsulating material form a unitary layer that serves an electronicfunction of the structural electronics wireless sensor node. FIG. 1Dillustrates a nanostructure layer of a structural electronics wirelesssensor node comprising parallel patterned nanostructures embedded in anelectrically insulating material. As shown in FIG. 1D, nanostructurelayer 114 comprises parallel patterned nanostructures 108 embedded inelectrically insulating matrix 112 a.

In certain embodiments, a second nanostructure layer of the structuralelectronics body comprises a second plurality of patternednanostructures embedded in an electrically insulating material. FIG. 2Aillustrates the introduction of a second substrate to a firstnanostructure layer comprising parallel patterned nanostructuresembedded in an electrically insulating matrix, according to certainembodiments. As shown in FIG. 2A, substrate 102 b (e.g., secondsubstrate), is introduced to nanostructure layer 114 (e.g., firstnanostructure layer) comprising parallel patterned nanostructures 108embedded in electrically insulating matrix 112 a. The secondnanostructure layer may be fabricated by the fabrication techniquesdescribed above with reference to FIG. 1A to FIG. 1D. Resultantly, FIG.2B illustrates a first nanostructure layer comprising parallel patternednanostructures embedded in an electrically insulating matrix and asecond nanostructure layer comprising parallel patterned nanostructuresembedded in an electrically insulating matrix, according to someembodiments. As shown in FIG. 2B, first nanostructure layer 114comprises parallel patterned nanostructures 108 embedded in structuralpolymer matrix 112 a and second nanostructure layer 214 comprisesparallel patterned CNTs 108 embedded in structural polymer matrix 112 b.According to certain embodiments, the first nanostructure layer and thesecond nanostructure layer may be designed and fabricated separately(e.g., in a step-wise fashion). In some other embodiments, the firstnanostructure layer and the second nanostructure layer may be designedand fabricated concurrently.

According to certain embodiments, the structural wireless sensor nodemay comprise more than two nanostructure layers. For example, thestructural wireless sensor node may comprise a plurality ofnanostructure layers (e.g., three, four, five, six, etc. nanostructureslayers) that each comprise parallel patterned nanostructures embedded inan electrically insulating matrix. In some embodiments, the plurality ofnanostructure layers (e.g., three, four, five, six, etc. nanostructureslayers) may be fabricated by the techniques described herein withreference to FIG. 1A to FIG. 1D.

According to some embodiments, the plurality of nanostructure layerseach serve a respective electronic function of the structuralelectronics wireless sensor node. For example, in some embodiments, thefirst nanostructure layer serves a first electronic function of thewireless sensor node and the second nanostructure layer serves a secondelectronic function of the wireless sensor node. FIG. 3A illustrates afirst nanostructure layer and a second nanostructure layer configured ina planar fashion forming a structural electronics wireless sensor node.Alternatively, FIG. 3B illustrates a first nanostructure layer and asecond nanostructure layer stacked vertically forming a structuralelectronics wireless sensor node. Referring to FIG. 3A and FIG. 3B,first nanostructure layer 114 comprising parallel patternednanostructures 109 embedded in electrically insulating matrix 112 aserves a first electronic function of the wireless sensor node, andsecond nanostructure layer 214 comprising parallel patterned CNTs 108embedded in structural polymer matrix 112 b serves a second electronicfunction of the wireless sensor node. As shown in FIG. 3A, edges offirst nanostructure layer 114 and second nanostructure layer 214intersect only at their endpoints. Alternatively, as shown in FIG. 3B,at least a portion of surface 118 a of first nanostructure layer 114overlaps with at least a portion of surface 118 b of secondnanostructure layer 214. According to certain embodiments, variouselectronic components of the structural electronics wireless sensor nodemay be fabricated by employing the same fabrication techniques withdifferent growth and/or patterning methods. Non-limiting examples ofcertain electronic components which may be formed from the nanostructure layers are described in further detail below.

In some embodiments, the first nanostructure layer comprising a firstplurality of patterned nanostructures embedded in an electricallyinsulating matrix is electrically coupled to the second nanostructurelayer of the body comprising a second plurality of patternednanostructures embedded in an electrically insulating matrix. Accordingto certain embodiments, the first nanostructure layer and the secondnanostructure layer are electrically coupled by one or more electricalconnections that bridge the first nanostructure layer and the secondnanostructure layer. Accordingly, in certain embodiments, the structuralelectronics wireless sensor node comprises an electrical connectionbetween the first nanostructure layer and the second nanostructure layerthat couples the first plurality of patterned nanostructures of thefirst nanostructure layer with the second plurality of nanostructures ofthe second nanostructure layer.

In some embodiments, the electrical connection may be a coupler. Incertain embodiments, the coupler may comprise one or morenanostructures, although other types of connections may be used inalternative embodiments. In certain non-limiting embodiments, thenanostructure coupler is a CNT coupler. In certain embodiments, theelectrical connection is a via. As shown in FIG. 3A and FIG. 3B, firstnanostructure layer 114 comprising parallel patterned nanostructures 108embedded in electrically insulating matrix 112 a and secondnanostructure layer 214 comprising parallel patterned nanostructures 204embedded in electrically insulating matrix 112 b are electricallycoupled through one or more electrical connections 106. In someembodiments, the first nanostructure layer and the second nanostructurelayer are coupled through one or more electrical connections 106 acrosssurface 118 a of first nanostructure layer and surface 118 b of secondnanostructure layer.

In some embodiments, the structural electronics wireless sensor node maybe particularly strong, stiff, and/or tough. Resultantly, the structuralelectronics wireless sensor node is configured to function as both anindividual structure and an electronics element. For example, in someembodiments, the strength (e.g., tensile strength), stiffness, and/ortoughness of the nanostructures is at least the same as the strength,stiffness, and/or toughness of the electrically insulating material. Forexample, in certain embodiments the structural electronics wirelesssensor node may have the same strain throughout the bulk of thematerial.

In certain embodiments, the structural electronics wireless sensor nodehas an elastic modulus. In some aspects, the axial elastic modulus ofthe structural electronics wireless sensor node is greater than or equalto 1 GPa, greater than or equal to 5 GPa, greater than or equal to 6GPa, greater than or equal to 7 GPa, greater than or equal to 8 GPa,greater than or equal to 9 GPa, or greater than or equal to 10 GPa. Insome embodiments, the axial elastic modulus of the structuralelectronics wireless sensor node is less than or equal to 15 GPa, lessthan or equal to 10 GPa, less than or equal to 9 GPa, less than or equalto 8 GPa, less than or equal to 7 GPa, or less than or equal to 6 GPa.Combinations of the above recited ranges are also possible. In certainembodiments, the transverse elastic modulus of the structuralelectronics wireless sensor node is greater than or equal to 1 GPa,greater than or equal to 3 GPa, greater than or equal to 4 GPa, greaterthan or equal to 5 GPa, greater than or equal to 6 GPa, greater than orequal to 7 GPa, greater than or equal to 8 GPa, greater than or equal to9 GPa, or greater than or equal to 10 GPa. In some embodiments, thetransverse elastic modulus of the structural electronics wireless sensornode is less than or equal to 15 GPa, less than or equal to 10 GPa, lessthan or equal to 9 GPa, less than or equal to 8 GPa, less than or equalto 7 GPa, or less than or equal to 6 GPa, less than or equal to 5 GPa,or less than or equal to 4 GPa. Combinations of the above recited rangesare also possible.

Some embodiments are related to a method of fabricating a structuralelectronics wireless sensor node. For example, FIG. 4 illustrates a flowchart describing a method of fabricating a wireless sensor node,according to certain embodiments. As shown in FIG. 4, method 400comprises step 404 comprising sputtering a solution of nanostructures(e.g., CNTs) on a substrate. In some embodiments, step 406 of method 600comprises introducing an electrically insulating material (e.g., astructural polymer) to provide parallel patterned nanostructuresembedded in a first electrically insulating matrix 406. In certainaspects, step 408 of method 600 comprises introducing a secondsubstrate, and step 410 comprises repeating steps 404 and 406 to provideparallel patterned nanostructures embedded in a second electricallyinsulating matrix. In some embodiments, method 600 further comprisesstep 412 comprising electrically coupling the first electricallyinsulating matrix and the second electrically insulating matrix via anelectrical connection. In certain aspects, the method may furthercomprise introducing additional substrates (e.g., a third substrate, afourth substrate, etc.), and repeating 404 to 406 to provide additionalnanostructure layers comprising parallel patterned nanostructuresembedded in an electrically insulating matrix, each of which may becoupled to the first electrically insulating matrix and/or the secondelectrically insulating matrix.

Various types of electronic components may be formed as part of themulti-layer structural electronics wireless sensor node. In someembodiments, for example, passive electronic components may be formed.In some aspects, the structural electronics wireless sensor node is apassive structural electronics wireless sensor node. In certainembodiments, active electronic components may be formed.

Certain embodiments described herein relate to structural electronicsRLC components. In some embodiments, the structural electronics wirelesssensor node comprises RLC components fabricated from nanostructurelayers comprising a plurality of patterned nanostructures embedded in astructural polymer matrix. For example, in certain embodiments, thestructural wireless sensor node may comprise a first nanostructurelayer, a second nanostructure layer, and a third nanostructure layerthat correspond to a resistor component, a inductor component, and acapacitor component, respectively. FIG. 5A illustrates a structuralwireless sensor node comprising a first nanostructure layer, a secondnanostructure layer, and a third nanostructure layer configured in aplanar fashion forming a structural electronics wireless sensor node,according to certain embodiments. Alternatively, FIG. 5C illustrates astructural wireless sensor node comprising a first nanostructure layer,a second nanostructure layer, and a third nanostructure layer stackedvertically forming a structural electronics wireless sensor node,according to some embodiments. As shown in FIGS. 5A and 5C, structuralelectronics wireless sensor node 150 comprises first nanostructure layer114, second nanostructure layer 214, and third nanostructure layer 314,which may correspond to a resistor component, a inductor component, anda capacitor component, respectively. According to certain embodiments,any combination of configurations related to the resistor, inductor,and/or capacitor may be envisioned such that each of the firstnanostructure layer, second nanostructure layer, and/or thirdnanostructure layer may correspond to the resistor component, inductorcomponent, and/or capacitor component.

According to certain embodiments, the resistor, inductor, and capacitorare components of the structural wireless sensor node. In someembodiments, the resistor, inductor, and/or capacitor of the structuralelectronics wireless sensor node are part of a circuit. In some aspects,the circuit is a RLC circuit, and the structural RLC components can bearranged in any of a variety of suitable manners as part of the circuit.In certain embodiments, the resistor, inductor, and/or capacitor arepart of a radio frequency (RF) impedance matching circuit. In someembodiments, the resistor, formed of nanostructures, may operate as asubstantially pure resistor even at radio frequencies, for example onthe order of 10⁸ Hz (e.g., up to 5×10⁸ Hz, up to 8×10⁸ Hz, or any othersuitable value). Referring to FIG. 5A and FIG. 5C, in certainembodiments, structural electronics wireless sensor node 150 is acircuit comprising a first nanostructure layer (e.g., a resistor), asecond nanostructure layer (e.g., an inductor), and a thirdnanostructure layer (e.g., a capacitor). In some embodiments, thewireless sensor node 150 is a RLC circuit.

According to some embodiments, the structural electronics resistor,inductor, and/or capacitor are used for wireless sensor networks andwireless tagging applications. FIG. 10A illustrates a resistor,inductor, and capacitor structural electronic components of a wirelesssensor node, according to certain embodiments. As shown in FIG. 10A,resistor 604 c, inductor 706 c, and resistor 802 b each comprise ananostructure layer comprising parallel patterned nanostructures 108embedded in structural polymer matrix 112. Alternatively, FIG. 10B showsa non-limiting embodiment of a structural electronics wireless sensornode comprising an inductor and a capacitor. As shown in FIG. 10B,structural electronics wireless sensor node 150 f comprises inductor 706d and capacitor 802 c. In some such embodiments, the inductor andcapacitor may have an intrinsic resistance (e.g., parasitic resistance),which causes the inductor to function as both an inductor and aresistor.

According to certain embodiments, a structural electronics resistor isprovided. In some embodiments, the resistor is a structural electronicscomponent that comprises a nanostructure layer comprising a plurality ofpatterned nanostructures embedded in an electrically insulating matrix.In certain aspects, the resistor may be positioned within a largercircuit or system to serve any of a variety of suitable purposes. Forexample, in some embodiments, the resistor may be used to provide aresistance, and its behavior may not be monitored. In some embodiments,the resistor may be used as a sensor, with the resistance beingmonitored to assess a condition of interest, such as an environmentcondition.

The resistor described herein may have any of a variety of suitableresistances values. For example, in certain embodiments the resistor hasa resistance of greater than or equal to 1 megaohm (Mohm), greater thanor equal to 25 Mohms, greater than or equal to 50 Mohms, greater than orequal to 75 Mohms, greater than or equal to 100 Mohms, greater than orequal to 125 Mohms, greater than or equal to 150 Mohms, greater than orequal to 175 Mohms, greater than or equal to 200 Mohms, greater than orequal to 225 Mohms, or greater than or equal to 250 Mohms. In someembodiments, the resistor has a resistance of less than or equal to 300Mohms, less than or equal to 250 Mohms, less than or equal to 225 Mohms,less than or equal to 200 Mohms, less than or equal to 175 Mohms, lessthan or equal to 150 Mohms, less than or equal to 125 Mohms, less thanor equal to 100 Mohms, less than or equal to 75 Mohms, less than orequal to 50 Mohms, or less than or equal to 25 Mohms. Combinations ofthe above recited ranges are also possible (e.g., the resistor has aresistance of greater than or equal to 1 Mohm and less than or equal to300 Mohms, the resistor has a resistance of greater than or equal to 50Mohms and less than or equal to 75 Mohms, etc.).

The resistor may be fabricated by any of a variety of suitabletechniques. For example, in some embodiments, a substrate may beprovided, and a forest of vertically aligned patterned nanostructuresare grown on the substrate. In some aspects, the forest of parallelpatterned nanostructures may be knocked own (e.g., with a roller, withsolvent, etc.), thereby providing a forest of parallel patternednanostructures on the substrate. In certain embodiments, an electricallyconductive material (e.g., a polymer) may then be drop casted onto theforest of parallel patterned nanostructures on the substrate, therebyproviding parallel patterned nanostructures embedded in a substrate. Insome aspects, the electrically conductive material may be spin-coated,cured, and/or delaminated, in order to provide the resistor. Withoutwishing to be bound by theory, any combination of the fabricationmethods described herein, with respect to a nanostructure layer, may beused in fabricating the resistor. FIG. 6 illustrates a non-limitingmethod of fabricating a resistor, according to certain embodiments. Insome aspects, as shown in FIG. 6, method of fabricating resistor 600comprises knocking down forest of parallel patterned nanostructures 104on substrate 102 using roller, thereby providing forest of parallelpatterned nanostructures 108 on substrate 102. In some embodiments,electrically insulating material 110 (e.g., structural polymer material)may be drop casted onto forest of parallel patterned nanostructures 108on substrate 102, resulting in resistor 604 a comprising a parallelpatterned nanostructures 108 embedded in structural polymer matrix 112.

As described herein, certain embodiments are related to a structuralelectronics inductor. In some embodiments, the inductor is a structuralelectronics component that comprises a nanostructure layer comprising aplurality of patterned nanostructures embedded in an electricallyinsulating matrix. The inductor may be positioned within a largercircuit or system to serve any of a variety of suitable purposes. Forexample, the inductor may be used to provide an electromagneticinductance, and its behavior may not be monitored. According to certainembodiments, the inductor may be used as a sensor, with theelectromagnetic inductance being monitored to assess a condition ofinterest, such as an environment condition. In some embodiments, theinductor is used to store the current of the structural electronicswireless sensor node.

The inductor may have any of a variety of suitable inductance values.For example, in certain embodiments the inductor has an inductance ofgreater than or equal to 1 nanohenrys (nH), greater than or equal to 5nH, greater than or equal to 10 nH, greater than or equal to 15 nH,greater than or equal to 20 nH, greater than or equal to 50 nH, orgreater than or equal to 100 nH. In some embodiments, the inductor hasan inductance of less than or equal to 200 nH, less than or equal to 100nH less than or equal to 50 nH, less than or equal to 20 nH, less thanor equal to 15 nH, less than or equal to 10 nH, or less than or equal to5 nH. Combinations of the above recited ranges are also possible (e.g.,the inductor has an inductance of greater than or equal to 1 nH and lessthan or equal to 200 nH, the inductor has an inductance of greater thanor equal to 15 nH and less than or equal to 50 nH, etc.).

The inductor may be fabricated by any of a variety of suitabletechniques. For example, according to some embodiments, the inductor maybe fabricated by providing a substrate and growing a forest ofvertically aligned patterned nanostructures on the substrate. In certainembodiments, the nanostructures may be grown using lithography to mask aparticular pattern on the substrate with an active growth material. Incertain embodiments, the forest of vertically aligned patternednanostructures can then be knocked down using the methods describedherein. In certain embodiments, an electrically conductive material(e.g., a polymer) may then be drop casted onto the forest of parallelpatterned nanostructures on the substrate, thereby providing parallelpatterned nanostructures embedded in the substrate. In some embodiments,the parallel patterned nanostructures embedded in the substrate may bedrop-casted, spin-coated, cured, and/or delaminated, in order to providethe inductor. Without wishing to be bound by theory, any combination ofthe fabrication methods described herein, with respect to ananostructure layer, may be used in fabricating the inductor. FIG. 4illustrates a non-limiting method of fabricating an inductor, accordingto some embodiments. In certain embodiments, substrate 102 is provided,and patterned with active growth material 702 (e.g, using lithographymasking techniques). According to some embodiments, a forest ofvertically aligned patterned nanostructures 104 are grown on substrate102, followed by knocking down the forest of vertically alignedpatterned nanostructures, drop-casting electrically insulating material110, and spin-coating 118, thereby providing inductor 706 comprisingforest of parallel patterned nanostructures 108 embedded in structuralpolymer matrix 112. FIG. 8 illustrates a series of fabricated inductors,according to certain embodiments, ranging in pattern and size.

Certain embodiments are related to a structural electronics capacitor.In some embodiments, the capacitor is a structural electronics elementthat comprises a nanostructure layer comprising a plurality of patternednanostructures embedded in an electrically insulating matrix. Thecapacitor may be positioned within a larger circuit or system to serveany of a variety of suitable purposes. For example, according to certainembodiments, the capacitor is configured to measure a capacitance, andits behavior may not be monitored. In certain embodiments, the capacitormay be used as a sensor, with the capacitance being monitored to assessa condition of interest, such as an environment condition. In someembodiments, the inductor is used to store a charge of the structuralelectronics wireless sensor node.

The capacitor may have any of a variety of suitable capacitance values.For example, in certain embodiments the capacitor has a capacitance ofgreater than 0 picofarads (pF), greater than or equal to 1 pF, greaterthan or equal to 2 pF, greater than or equal to 4 pF, greater than orequal to 6 pF, greater than or equal to 8 pF, greater than or equal to10 pF, or greater than or equal to 12 pF. In some embodiments, thecapacitor has a capacitance of less than or equal to 15 pF, less than orequal to 12 pF, less than or equal to 10 pF, less than or equal to 8 pF,less than or equal to 6 pF, less than or equal to 4 pF, less than orequal to 2 pF, or less than or equal to 1 pF. Combinations of the aboverecited ranges are also possible (e.g., the capacitor has a capacitanceof greater than 0 pF and less than or equal to 12 pF, the capacitor hasa capacitance of greater than 4 pF and less than or equal to 10 pF,etc.).

The capacitor may be fabricated by any of a variety of suitabletechniques. For example, in some embodiments, a substrate is provided,and a forest of vertically aligned patterned nanostructures are grown onthe substrate. In some aspects, the forest of parallel patternednanostructures may be knocked down, thereby providing a forest ofparallel patterned nanostructures on the substrate. In certainembodiments, an electrically conductive material (e.g., a polymer) maythen be drop casted onto the forest of parallel patterned nanostructureson the substrate, thereby providing parallel patterned nanostructuresembedded in a substrate. In some aspects, the parallel patternednanostructures embedded in a substrate may be spin-coated, cured, and/ordelaminated, in order to provide the capacitor. Without wishing to bebound by theory, any combination of the fabrication methods describedherein, with respect to a nanostructure layer, may be used infabricating the capacitor. FIG. 9 illustrates a non-limiting method offabricating a capacitor, according to some embodiments. In certainembodiments, forest of parallel patterned nanostructures 108 on asubstrate 102 are subjected to two iterations of drop casting anelectrically insulating material 110 and spin-coating 118, therebyproviding parallel patterned nanostructures embedded in an electricallyinsulating matrix. In certain embodiments, parallel patternednanostructures embedded in an electrically insulating matrix are thencured, thereby providing capacitor 802 a.

Certain embodiments described herein relate to an antenna (e.g., aflexible patch antenna). In some embodiments, the antenna is astructural electronics element that comprises a nanostructure layercomprising a plurality of patterned nanostructures embedded in anelectrically insulating matrix.

According to certain embodiments, the flexible patch antenna may beconfigured to flex. FIG. 13A illustrates a perspective view of aflexible patch antenna, according to certain embodiments. While FIG. 13Aillustrates a flexible patch antenna being flexed in a single direction,it should be appreciated that the flexible patch antenna may be flexedin any suitable direction. In some embodiments, flexible patch antenna950 a comprises a plurality of parallel patterned nanostructures 108embedded in a structural polymer matrix 112. In some embodiments, theflexible patch antenna is configured to harvest energy (e.g.,radiofrequency energy). In certain embodiments, the flexible patchantenna is configured to route the energy captured to a desireddestination (e.g., a second nanostructure layer of a wireless sensornode that serves an additional electronic function other than theantenna).

Some embodiments relate to a method of fabricating a flexible patchantenna. For example, in some embodiments, a forest of verticallyaligned patterned nanostructures are grown on a substrate. In someembodiments, the forest of vertically aligned patterned nanostructuresare knocked down using any of a variety of suitable methods describedherein (e.g., with a roller, with a solvent), thereby providing a forestof parallel patterned nanostructures on the substrate. According tocertain embodiments, an electrically insulating material (e.g.dielectric polymer, EPON) added to the forest of parallel patternednanostructures on the substrate by any of a variety of suitable methods(e.g., drop casting), thereby providing parallel patternednanostructures embedded in a structural polymer matrix is provided.According to certain embodiments, the flexible patch antenna may beprotected with a layer of polymeric adhesive, such as polyethyleneterephthalate (PET). Without wishing to be bound by theory, anycombination of the fabrication methods described herein, with respect toa nanostructure layer, may be used in fabricating the antenna. FIG. 12is a flow chart of a non-limiting method of fabricating a flexible patchantenna, according to certain embodiments. In FIG. 12 and according tocertain embodiments, method of fabricating flexible patch antenna 500comprises step 904 comprising sputtering a solution of nanostructures ona substrate 904. Step 904 of method 900 is followed by step 906, whichcomprises introducing an electrically insulating material to provideparallel patterned nanostructures embedded in an electrically insulatingmatrix. Method 900 optionally comprises step 908, comprising protectingthe nanostructures embedded in the electrically insulating matrix (e.g.,with a polymeric adhesive). FIG. 13B shows a fabricated flexible patchantenna, according to certain embodiments. In certain embodiments,electronic device 952 may be disposed on the backside of the flexiblepatch antenna 950 c. In certain embodiments, a fabricated flexible patchantenna may have a length and/or width of greater than or equal to 0.5inches, greater than or equal to 1 inch, greater than or equal to 1.5inches, greater than or equal to 2 inches, and the like.

According to certain non-limiting embodiments, a first electroniccomponent of the structural electronics wireless sensor node is anantenna and a second electronic component of the structural electronicswireless sensor node is an energy harvester. For example, in someaspects, the structural electronics wireless sensor node includes anantenna and a sensor (e.g., a sensing element) that communicatewirelessly by altering an impedance of the antenna. In certainembodiments, the structural wireless sensor node includes an antenna, anenergy harvesting device, and an energy storage device. In someembodiments, the energy harvester may harvest energy from carriersignals received at the antenna. For example, the antenna can have avariety of suitable frequency responses for S11 input/outputrelationships. The antenna may have a frequency response of greater thanor equal to 0.5 GHz, greater than or equal to 1.0 GHz, greater than orequal to 1.5 GHz, greater than or equal to 2.0 GHz, or greater than 2.5GHz. In certain other embodiments, the energy harvester may be athermoelectric harvester, vibrational harvester, or photovoltaicharvester. In some embodiments, the harvested energy may be stored in anenergy storage component formed as a different nanostructure layer ofthe multi-layer structural electronics wireless sensor node.

According to some embodiments, the energy harvester is a RF far fieldharvester. According to certain embodiments, RF signals used by thesensor node may include signals such as a 2.4 GHz continuous wave (CW)carrier signal. As such, the antenna may be a 2.4 GHz antenna in someembodiments, although other frequencies may be used. In someembodiments, the antenna is configured for RF far field energyharvesting and backscattering communication by altering its RFimpedance.

In some embodiments, the flexible patch antenna is a sensor data link(e.g., a passive sensor data link). In certain aspects, the flexiblepatch antenna can control and/or alter impedance. As a result, accordingto certain embodiments, the flexible patch antenna can communicatewirelessly through backscattering communication to other nanostructurelayers serving a different electronic function of the wireless sensornode (e.g., a sensing element).

In certain non-limiting embodiments, a first electronic component is asensing element (e.g., general sensor) and a second electronic componentis an antenna. In some aspect, the sensing element is a corrosion sensorand/or crack sensor.

According to some embodiments, the sensing element (e.g., corrosionsensor, crack sensor), energy harvester, and/or antenna are disposed inrespective nanostructure layers of the plurality of nanostructure layersof the structural electronics wireless sensor node.

In some embodiments, one or more of the resistor, inductor, andcapacitor structural electronics components are necessary to match theimpedance between an antenna and a sensor node in order to achievemaximum energy transfer. For example, FIG. 11 illustrates an impedancematching element of a wireless sensor node. In some embodiments, theimpedance matching element could be formed using the resistor, inductor,and capacitor structural electronic components. The impedance matchingnetwork may be a radio frequency (RF) impedance matching network. Theresistor may function as a resistor at radio frequencies. Accordingly,in certain embodiments, it may be particularly useful for the structuralwireless sensor node to comprise a resistor, an inductor, a capacitor,and an antenna.

In some embodiments, the structural electronics wireless sensor nodecomprises at least four nanostructures layers. FIG. 5B illustrates astructural wireless sensor node comprising a first nanostructure layer,a second nanostructure layer, a third nanostructure layer, and a fourthnanostructure layer configured in a planar fashion forming a structuralelectronics wireless sensor node, in accordance with some embodiments,and FIG. 5D illustrates a structural wireless sensor node comprising afirst nanostructure layer, a second nanostructure layer, a thirdnanostructure layer, and a fourth nanostructure layer stacked verticallyforming a structural electronics wireless sensor node, in accordancewith certain embodiments. As shown in FIG. 5B and FIG. 5D, structuralelectronics wireless sensor node 150 comprises first nanostructure layer114, second nanostructure layer 214, third nanostructure layer 314, andfourth nanostructure layer 414, which may correspond to a resistorcomponent, a inductor component, a capacitor component, and an antennacomponent, respectively.

FIG. 5E illustrates a structural wireless sensor node comprising a firstnanostructure layer, a second nanostructure layer, a third nanostructurelayer, and a fourth nanostructure layer, wherein at least a portion ofthe nanostructure layers are configured in a planar fashion and at leasta portion of the nanostructure layers are stacked vertically, inaccordance with certain embodiments. For example, as shown in FIG. 5E,first nanostructure layer 114, second nanostructure layer 214, and thirdnanostructure layer 314 are configured in a planar fashion. Fourthnanostructure layer 414, however, is layered on top of firstnanostructure layer 114 and second nanostructure layer 214. In certainembodiments, it may be particularly useful to employ such configurationswhen the structural electronics wireless sensor node comprises aresistor, inductor, capacitor, and antenna. In some such embodiments,the structural electronics wireless sensor node may comprise the RLCcomponents in a planar fashion, with the antenna layered on top of oneor more of the RLC components. In certain embodiments, the antenna maybe layered on top of the RLC components due to its large surface area(e.g., length and/or width greater than 0.5 inches, greater than 1.0inches, greater than 1.5 inches, etc.).

Various other types of electronic components and/or configurations ofthe multi-layer structural electronics wireless sensor node may beemployed. For example, in certain embodiments, the structuralelectronics wireless sensor node may comprise a transistor, such as afield-effect transistor (FET). In some embodiments, the structuralelectronics wireless sensor node comprises a diode. In certain aspects,the structural electronics wireless sensor node comprises a rectifier.In some embodiments, filters, switches, and/or logic gates may beformed. In some embodiments, the structural electronics wireless sensornode comprises a data link layer formed in a respective nanostructurelayer of the plurality of nanostructure layers. According to someembodiments, the structural electronics wireless sensor node comprises apower management module formed in a respective nano structure layer ofthe plurality of nanostructure layers.

FIG. 14 illustrates an exemplary embodiment of a wireless structuralelectronic sensor node, according to some embodiments. Referring to FIG.14, structural electronics wireless sensor node 150 g may compriseimpedance matching element 962, energy harvester electronic component964 (e.g., a RF far field harvester), general-purpose input/outputcomponent 966, corrosion sensor 968, amplitude-shift keying modulator970, and/or amplitude-shift keying demodulator 972.

According to certain embodiments, one or more nanostructure layerscomprising a plurality of patterned nanostructures embedded in anelectrically insulating matrix may be integrated into manufacturedproducts, thereby enabling structural electronics advancedmanufacturing. For example, FIG. 15 illustrates the integration of astructural wireless sensor node into a manufactured product. In certainembodiments, the manufactured product is a land system and/or vehicle, awater system and/or vehicle, an air system and/or vehicle, and/or aspace system and/or vehicle. As shown in FIG. 15, the manufacturedproduct is an airplane. In certain embodiments, the structuralelectronics wireless sensor node causes less than 5%, less than 10%,less than 20%, less than 30%, less than 40%, less than 50%, less than75%, less than 100%, less than 200%, less than 300%, or less than 500%increase in maximum strain throughout the product it is being integratedinto.

According to some embodiments, manufacturing products with a structuralelectronics sensor enables smart maintenance applications to monitor andschedule maintenance cycles based on the structure health of thewireless sensor node, and not just on planned maintenance periods withcondition-based monitoring, non-destructive evaluation, structuralhealth monitoring, and/or health usage monitoring system applications.

In certain embodiments, the antenna powered by energy harvesting may beused for any of a variety of applications, including in military,healthcare, and industrial settings. For example, a flexible pathantenna may be disposed on a piece of industrial machinery to harvestenergy and to power a sensor monitoring operation of the machinery.

According to certain embodiments, the nanostructures have at least onecharacteristic dimension (e.g., cross-sectional dimension) of less thanor equal to 500 nm, less than or equal to 250 nm, less than or equal to100 nm, less than or equal to 75 nm, less than or equal to 50 nm, lessthan or equal to 25 nm, less than or equal to 10 nm, or, in some cases,less than or equal to 1 nm. Nanostructures described herein may have, insome cases, a maximum characteristic dimension (e.g., maximumcross-sectional dimension) of less than 1 micrometer, less than or equalto 500 nm, less than or equal to 250 nm, less than or equal to 100 nm,less than or equal to 75 nm, less than or equal to 50 nm, less than orequal to 25 nm, less than or equal to 10 nm, or, in some cases, lessthan or equal to 1 nm.

In certain embodiments, the nanostructures may be elongatednanostructures with high aspect ratios. For example, in certainembodiments, the nanostructures may have a length of greater than orequal to 0.1 micrometers, greater than or equal to 1 micrometer, greaterthan or equal to 50 micrometers, greater than or equal to 100micrometers, greater than or equal to 200 micrometers, greater than orequal to 300 micrometers, or greater than or equal to 400 micrometers.

In some embodiments, the forest of nanostructures comprises at least 5,at least 10, at least 50, at least 100, at least 500, at least 1000, orat least 10,000 nanostructures. In some such embodiments, the forest ofnanostructures may comprise at least 10⁶, at least 10⁷, at least 10⁸, atleast 10⁹, at least 10¹⁰, at least 10¹¹, at least 10¹², or at least 10¹³nanostructures. Those of ordinary skill in the art are familiar withsuitable methods for forming forests of nanostructures. For example, insome embodiments, the forest of nanostructures can be catalyticallygrown (e.g., using a growth catalyst deposited via chemical vapordeposition process). In some embodiments, the as-grown forest can beused as is, while in other cases, the as-grown forest may bemechanically manipulated after growth and prior to subsequent processingsteps described elsewhere herein (e.g., folding, shearing, compressing,buckling, etc.).

In some cases, CNTs may resemble a sheet of graphite formed into aseamless cylindrical structure. In some cases, CNTs may include a wallthat comprises fine-grained sp² sheets. In certain embodiments, CNTs mayhave turbostratic walls. It should be understood that the CNT may alsocomprise rings or lattice structures other than six-membered rings.Typically, at least one end of the CNT may be capped, i.e., with acurved or nonplanar aromatic structure. In some cases, the CNTs may havea diameter of the order of nanometers and a length on the order ofmillimeters, or, on the order of tenths of micrometers, resulting in anaspect ratio greater than 100, 1000, 10,000, 100,000, 10⁶, 10⁷, 10⁸,10⁹, or greater. Examples of CNTs include single-walled carbon nanotubes(SWCNTs), double-walled carbon nanotubes (DWCNTs), multi-walled carbonnanotubes (MWCNTs) (e.g., concentric carbon nanotubes), inorganicderivatives thereof, organic derivatives thereof, and the like. In someembodiments, the CNT is a single-walled CNT. In some cases, the CNT is amulti-walled CNT (e.g., a double-walled CNT). In some cases, the CNTcomprises a multi-walled or single-walled CNT with an inner diameterwider than is attainable from a traditional catalyst or other activegrowth material. In some cases, the CNT may have a diameter less than 1micrometer, less than 500 nm, less than 250 nm, less than 100 nm, lessthan 50 nm, less than 25 nm, less than 10 nm, or, in some cases, lessthan 1 nm.

The terms “approximately”, “substantially,” and “about” may be used tomean within +/−20% of a target value in some embodiments, within +/−10%of a target value in some embodiments, within +/−5% of a target value insome embodiments, and yet within +/−2% of a target value in someembodiments. The terms “approximately” and “about” may include thetarget value.

The following examples are intended to illustrate certain embodiments ofthe present technology, but do not exemplify the full scope of thetechnology.

EXAMPLES

The following examples show data related to the electronic properties ofstructural electronics wireless sensor nodes.

FIG. 16 shows insertion loss S 11 as a function of frequency for afabricated antenna, according to certain embodiments. As shown in FIG.16, a fabricated patch antenna has a 1.8 GHz frequency response with aninsertion loss S11 of −1 dB, indicating that the flexible patch antennacan harvest energy oscillating at that frequency.

Various CNT-based structural electronics components were fabricated andtested, as now described. A CNT structural electronics resistor wasfabricated, of the type illustrated in FIG. 10A as resistor 604 c. Theelectronic properties were determined, as shown in FIGS. 17A-17D. FIG.17A shows a plot of the resistivity of the structural electronicsresistor with CNTs as a function of the CNT length (measured inmicrons). Three data sets are illustrated, including “perpendicular,”“parallel,” and “anisotropy.” The “perpendicular” data reflects theresistivity of the structural electronics resistor as measuredperpendicular to the axis of the CNTs. The “parallel” data representsthe resistivity as measured parallel to the CNT axis. The “anisotropy”data represents the anisotropy of the structure. FIG. 17B shows a plotof the sheet resistance of a structural electronics resistor with CNTsas a function of the CNT length (in microns). Data is shown for twodifferent resistors, one being a 300 micron resistor (line 1702) and theother being a 50 micron resistor (line 1704). FIG. 17C shows a plot ofthe impedance of a structural electronics resistor with CNTs as afunction of frequency (in Hz), according to certain embodiments, asmeasured parallel to the CNT axis. Data is shown for each of fourresistor lengths, including 50 microns, 150 micron, 300 microns, and 500microns. Specifically, line 1704 is the real impedance for a 50 micronresistor, line 1706 is the real impedance for a 300 micron resistor,line 1708 is the real impedance for a 150 micron resistor, and line 1710is the real impedance for a 500 micron resistor. Line 1712 is theimaginary impedance for a 150 micron resistor, line 1714 is theimaginary impedance for a 500 micron resistor, line 1716 is theimaginary impedance for a 50 micron resistor, and line 1718 is theimaginary impedance for a 300 micron resistor. FIG. 17D shows analternate plot to that of FIG. 17C, as measured perpendicular to the CNTaxis of the structural electronics resistor. Specifically, line 1720 isthe real impedance for a 50 micron resistor, line 1722 is the realimpedance for a 150 micron resistor, line 1724 is the real impedance fora 300 micron resistor, and line 1726 is the real impedance for a 500micron resistor. Line 1728 is the imaginary impedance for a 150 micronresistor, line 1730 is the imaginary impedance for a 500 micronresistor, line 1732 is the imaginary impedance for a 300 micronresistor, and line 1734 is the imaginary impedance for a 50 micronresistor.

The piezeoresistivity of a structural electronics resistor with CNTs wasevaluated. FIG. 18A shows the set-up for testing the piezoresistivity ofa structural electronics resistor, according to certain embodiments. Theresistor (left image), wiring (center image), and testing apparatus(right) are shown. FIG. 18B shows the piezoresistivity results. Stressof the structural electronics resistor is shown as a function ofmicrostrain, as is dR/R, according to some embodiments. Axial stress anddR/R and transverse stress and dR/R conditions are shown. The darkcircles and triangles illustrate axial stress and dR/R, and the whitecircles and triangles represent transverse stress and dR/R. FIG. 18Cshows a plot of the gauge factor of a structural electronics resistor asa function of microstrain for axial conditions (circles) and transverseconditions (triangles), according to certain embodiments.

The properties of a structural electronics capacitor with CNTs was alsoevaluated. The structural electronics capacitor was of the type shown inFIG. 10B as capacitor 802 c. FIG. 19A shows a plot of the impedance of astructural electronics capacitor as a function of frequency, accordingto some embodiments. FIG. 19B shows the reactance of the structuralelectronics capacitor as a function of frequency, according to certainembodiments. The capacitor represented in both figures had a spacing ofapproximately 0.5 mm between interdigitated fingers, represented by “s”in the plots.

The properties of a structural electronics inductor with CNTs was alsoevaluated. The inductor was of the type shown in FIG. 10A as inductor706 c. FIG. 20A shows a plot of the impedance of a structuralelectronics inductor as a function of frequency, according to someembodiments. Data for three different inductors of different sizes isshown. L_(o) represents the length of one side of the outermost loop ofthe inductor. Data for three values of L_(o) is shown in the plot. FIG.20B shows the reactance of the structural electronics inductors forwhich the impedance is shown in FIG. 20A.

The dynamic mechanical analysis of a polymer nanocomposite with CNTs wasevaluated. The samples were tested in a tensile configuration axial andtransverse to the nanostructure axis (e.g., CNT alignment). FIG. 21Ashows the dynamic mechanical analysis of a polymer nanocomposite withCNTs of length 50 microns, 150 microns, and 500 microns. EPON is alsoshown. The tensile stress for FIG. 21A is aligned with the CNT axis. InFIG. 21A, line 2102 refers to the storage modulus of a polymernanocomposite with CNTs of length 50 microns; line 2104 refers to thestorage modulus of a polymer nanocomposite with CNTs of length 500microns; line 2106 refers to the storage modulus of a polymernanocomposite of length 150 microns; and line 2108 refers to the storagemodulus of EPON. Also shown in FIG. 21A, line 2110 refers to the tandelta of a polymer nanocomposite with CNTs of length 50 microns; line2112 refers to the tan delta of a polymer nanocomposite with CNTs oflength 500 microns; line 2114 refers to the tan delta of a polymernanocomposite of length 150 microns; and line 2116 refers to the tandelta of EPON. FIG. 21B shows the same type of data as FIG. 21A, but forthe situation in which the tensile stress is perpendicular to the CNTaxis. FIG. 21C shows the dynamic mechanical analysis of a polymernanocomposite with CNTs as a function of CNT length, according to someembodiments.

The capacitance and inductance of a structural electronics capacitor andinductor, respectively, were evaluated. FIG. 22A shows a plot of thecapacitance of a structural electronics capacitor as a function offrequency. FIG. 22B shows a plot of the inductance of a structuralelectronics inductor as a function of frequency.

What is claimed:
 1. A structural electronics wireless sensor node,comprising: a first nanostructure layer comprising a first plurality ofpatterned nanostructures embedded in an electrically insulating matrix,wherein the first nanostructure layer serves a first electronic functionof the wireless sensor node; and a second nanostructure layer comprisinga second plurality of patterned nanostructures embedded in anelectrically insulating matrix, wherein the second nanostructure layerserves a second electronic function of the wireless sensor node, andwherein the first nanostructure layer is electrically coupled to thesecond nanostructure layer.
 2. The structural electronics wirelesssensor node of claim 1, wherein the first and second pluralities ofpatterned nanostructures comprise carbon nanotubes.
 3. The structuralelectronics wireless sensor node of claim 1, further comprising a thirdnanostructure layer coupled to the first nanostructure layer and/orsecond nanostructure layer and that is a general sensor, corrosionsensor, crack sensor, energy harvester, and/or antenna.
 4. Thestructural electronics wireless sensor node of claim 1, wherein theelectrically insulating matrix in which the first plurality of patternednanostructures is embedded is a structural polymer matrix.
 5. Thestructural electronics wireless sensor node of claim 4, wherein thestructural polymer matrix has an axial elastic modulus greater than orequal to 1 GPa.
 6. The structural electronics wireless sensor node ofclaim 1, wherein the structural electronics wireless sensor node isconfigured to monitor structural health.
 7. The structural electronicswireless sensor node of claim 1, wherein the first nanostructure layeris an antenna and the second nanostructure layer is a sensing element.8. The structural electronics wireless sensor node of claim 1, furthercomprising a third nanostructure layer comprising a third plurality ofpatterned nanostructures embedded in an electrically insulating matrix,wherein the first nanostructure layer is a resistor, the secondnanostructure layer is an inductor, and the third nanostructure layer isa capacitor.
 9. The structural electronics wireless sensor node of claim1, wherein at least a portion of the first and second nanostructurelayers are stacked vertically.
 10. The structural electronics wirelesssensor node of claim 1, wherein the first and second nanostructurelayers are positioned in a same plane.
 11. The structural electronicswireless sensor node of claim 1, further comprising a thirdnanostructure layer coupled to the first nanostructure layer and/orsecond nanostructure layer, wherein the third nanostructure layer is adata link layer.
 12. The structural electronics wireless sensor node ofclaim 1, further comprising a third nanostructure layer coupled to thefirst nanostructure layer and/or second nanostructure layer, wherein thethird nanostructure layer is a power management module.
 13. Thestructural electronics wireless sensor node of claim 1, wherein thefirst nanostructure layer comprises a diode.
 14. The structuralelectronics wireless sensor node of claim 1, wherein the firstnanostructure layer comprise a field-effect transistor.
 15. Thestructural electronics wireless sensor node of claim 1, furthercomprising a third nanostructure layer comprising a third plurality ofpatterned nanostructures embedded in an electrically insulating matrix,wherein the first nanostructure layer comprises a resistor, the secondnanostructure layer comprises an inductor, and the third nanostructurelayer comprises a capacitor, and wherein the resistor, inductor, andcapacitor form part of an RLC circuit.
 16. The structural electronicswireless sensor node of claim 1, wherein the first nanostructure layerand the second nanostructure layer are electrically coupled by anelectrical connection bridging the first nanostructure layer and thesecond nanostructure layer.
 17. The structural electronics wirelesssensor node of claim 16, wherein the electrical connection is a CNTcoupler.
 18. A method of fabricating a structural electronics wirelesssensor node, wherein the structural electronics wireless sensor nodecomprises a plurality of nanostructure layers, the method comprising:depositing elongated nanostructures on a substrate such that theelongated nanostructures are parallel within a patterned forest;providing an electrically insulating material; embedding the patternedforest of the nanostructures in the electrically insulating material,thereby providing a first nanostructure layer comprising parallelpatterned elongated nanostructures embedded in an electricallyinsulating matrix; electrically coupling the first nanostructure layerto at least a second nanostructure layer comprising parallel patternednanostructures embedded in an electrically insulating matrix; andintegrating the structural wireless sensor node into a manufacturedproduct.
 19. The method of claim 18, wherein each nanostructure layerserves an electronic function of the wireless sensor node.
 20. Astructural electronics wireless sensor node, comprising: a plurality ofnanostructure layers, each layer comprising respective pluralities ofpatterned nanostructures embedded in an electrically insulating matrix,wherein a first nanostructure layer is a resistor of the wireless sensornode, a second nanostructure layer is an inductor of the wireless sensornode, and a third nanostructure layer is a capacitor of the wirelesssensor node; and an electrical connection between the plurality ofnanostructure layers.